If you have taught a course on MongoDB, Express, React and Node, what textbook would you recommend? I'm particularly interested in open source textbooks authored on Github. But I'm open to anything.
But I will try to answer this question through my experience.
express is relative stable, express remains in 4.x for couple of years, which is quite unusual in js world. I don't recommend books for express. Its website is good enough. Other knowledge about express may just gain from programming.
To know express well, knowing node.js and its ecosystem is a must. When I learned nodejs back then I did buy the book "Node.js 8 the Right Way" and borrowed the book "Node.js in Action" But I will argue that no books about nodejs can keep up with the changes in nodejs world. So maybe just read the articles you google. But I notices I read a lot from https://dev.to/ , https://2ality.com/ & https://blog.logrocket.com/
Though my limited experience with MongoDB, I didn't like it at all, to me it is a poor product. There is old article called "Don't use MongoDB" which I resonate a lot "if you're writing a toy site, or a prototype, something where developer productivity trumps all other considerations,it basically doesn't matter what you use. Use whatever gets the job done." On quora there is a topic called "How much credibility does the post "Don't use MongoDB" have?" One of answers was provided by a guy called Gaëtan Voyer-Perrault. He answered a lot question about MongoDB, for example you may check his answer "Which companies have moved away from MongoDB and why? What did they move to?"
Having said that I need to emphasize that it was based on my experience in 2017 & 2018. I don't how much has changed since then.
Knowing the concept of no-sql, key value store is probably equally important if someone wants to know mongo. So maybe you can teach your student redis. To learn redis I will recommend "redis in action", it is free ebook you can read here https://redislabs.com/ebook/redis-in-action/
A project not too simple and not complicated to tinker with is important. I remembered I played with this https://github.com/OmarElGabry/chat.io a lot, "A Real Time Chat Application built using Node.js, Express, Mongoose, Socket.io, Passport, & Redis." I also tried meteor but I find it is too complicated for beginner and maybe not a good choice for a full stack app. But that is just my assessment.
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Using a CSS framework is probably another must in 2021, but there are so many CSS frameworks out there it is hard to choose an appropriate one. I don't have an answer for CSS.